As shown in FIG. 1, the 3rd Generation Partnership Project (3GPP) Evolved Packet System (EPS) consists of an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), a Mobility Management Entity (MME), a Serving Gateway (S-GW), a Packet Data Network Gateway (PDN GW or P-GW), a Home Subscriber Server (HSS), a 3GPP Authentication, Authorization and Accounting (AAA) server, a Policy and Charging Rules Function (PCRF) and other supporting nodes.
The MME is used for control plane related work, such as mobility management, processing of non-access layer signaling and management of user mobility management context. The S-GW which is an access gateway device connecting with the E-UTRAN is used to transfer data between the E-UTRAN and the P-GW and cache paging and waiting data. The P-GW which is a border gateway between the EPS and the PDN is used for access of the PDN and transfer of data between the EPS and the PDN.
The EPS supports interworking with a non-3GPP system, which is implemented through S2a, S2b and S2c interfaces. The P-GW acts as an anchor point between the 3GPP system and the non-3GPP system. The non-3GPP system is classified as trusted non-3GPP access system and untrusted non-3GPP access system. The trusted non-3GPP access system can be connected to the P-GW directly through the S2a interface; while the untrusted non-3GPP access system is required to be connected to the P-GW through an Evolved Packet Data Gateway (ePDG). Between the ePDG and the P-GW is the S2b interface. The S2c interface offers user plane related control and mobility support between a user equipment (UE) and the P-GW. The supported mobility management protocol is the Mobile IPv6 support for dual stack Hosts and Routers (DSMIPv6).
The EPS system introduces a Policy and Charging Control (PCC) function framework for dynamically controlling policy and charging of service access of users. Each logic function entity and its interface function in a Rel-8 PCC non-roaming scene architecture shown in FIG. 2 will be described below
An Application Function (AF) is used to offer access points for service applications. Network resources used by these service applications need dynamic policy control. When parameters negotiation at a service plane is implemented, the AF transfers the related service information to the Policy and Charging Rules Function (PCRF). If the service information is consistent with the policy of the PCRF, the PCRF will accept the negotiation; otherwise, the PCRF rejects the negotiation and gives its acceptable parameters upon feedback. Afterwards, the AF may return these parameters to the user equipment (UE). Between the AF and the PCRF is an Rx interface.
The PCRF is the core of the PCC and is responsible for making policy decision and charging rules. The PCRF offers service data flow based network control rules, which comprise detection of the service data flow, gating control, QoS (Quality of Service) control and data flow based charging rules. The PCRF sends its constituted policy and charging rules to a Policy and Control Enforcement Function (PCEF) for enforcement; meanwhile, the PCRF also needs to guarantee the consistency of these rules and user subscription information. The basis for the PCRF to constitute the policy and charging rules is to obtain service related information from the AF, acquire the subscription information associated with user policy and charging control from a Subscription Profile Repository (SPR), and acquire information of bearing related network from the PCEF through a Gx interface.
The PCEF is usually located in a gateway (GW) and executes the policy and charging rules made by the PCRF at a bearing plane. The PCEF detects service data flows according to a service data flow filter in the rules sent by the PCRF, and further executes the policy and charging rules made by the PCRF for the service data flows. When a bearer is established, the PCEF performs QoS authorization according to the rules sent by the PCRF and performs the gateway control according to the AF's enforcement. Meanwhile, the PCEF triggers and reports events occurring in the bearing network according to events subscribed by the PCRF. According to the charging rules sent by the PCRF, the PCEF performs a corresponding service data flow charging operation, which may be online charging or offline charging. If it is the online charging, the PCEF needs to manage credit together with an online charging system (OCS). When it is the offline charging, the PCEF exchanges the related charging information with an offline charging system (OFCS). An interface between the PCEF and the PCRF is a Gx interface, an interface between the PCEF and the OCS is a Gy interface, and an interface between the PCEF and the OFCS is a Gz interface. The PCEF is generally located in a network gateway, such as a Packet Data Network Gateway (PDN-GW) of the EPS, a General Packet Radio Service (GPRS) Gateway Supporting Node (GGSN) in the GPRS and a Packet Data Gateway (PDG) in an Interworking WLAN (I-WLAN).
A Bearer Binding and Event Reporting Function (BBERF) is generally located in an access network gateway. For example, when the UE accesses the EPS through the E-UTRAN using the Proxy Mobile Internet Protocol version 6 (PMIPv6) between the S-GW and the P-GW, the BBERF exists in the S-GW. When the UE accesses the EPS through the trusted non-3GPP access network, the BBERF also exists in the trusted non-3GPP access gateway. The objective of introducing the BBERF is that when the Mobile Internet Protocol (MIP) is used between the access network gateway and the P-GW, the PCEF cannot establish, modify and delete the bearer according to the PCC rules, meanwhile, it possibly cannot report the triggered events. At this point, the establishment, modification and deletion of the bearer as well as the event reporting function are performed by the BBERF. The PCRF interacts with the BBERF through a Gxx interface.
The subscription profile repository (SPR) stores the subscription information associated with policy and charging control of users. Between the SPR and the PCRF is a Sp interface.
The online charging system (OCS) controls and manages the user's credit in an online charging mode together with the PCFF.
The offline charging system (OFCS) performs a charging operation in an offline charging mode together with the PCFF.
The AF is required to subscribe an AF signaling transmission path state notification at the PCRF. After the PCRF receives the AF's subscription, it subscribes the corresponding event trigger at the PCEF. When the PCEF detects the corresponding event (e.g., lose or release of the bearer for transmitting the AF signaling), it reports the lose or release of the bearer for transmitting the AF signaling to the PCRF, which, in turn, notifies the AF of the event (or referred to as state).
When the user equipment accesses the EPS through the E-UTRAN using the PMIPv6 between the S-GW and the P-GW, or when the user equipment accesses the EPS through the trusted non-3GPP access network using the PMIPv6 between the trusted non-3GPP access network and the P-GW, or when the user equipment accessed the EPS through the trusted non-3GPP access network using the DSMIPv6 (Dual Stack Mobile Internet Protocol version 6) or MIPv4, the PCEF located in the P-GW cannot detect the loss or release of the bearer for transmitting the AF signaling. At this point the PCRF can only subscribe the loss and release of the bearer for transmitting the AF signaling event trigger at the BBERF, which detects and reports this event to the PCRF, which, in turn, reports this event to the AF.
In addition, the AF may also subscribe an IP-Connectivity Access Network (IP-CAN) type change notification at the PCRF. After the PCRF receives the AF's subscription, it subscribes the event trigger at the BBERF, which detects and reports the event to the PCRF. The BBERF reports the IP-CAN type as well as the specific radio access technology (RAT) type change in the IP-CAN type to the PCRF, which, in turn, reports this information to the AF.
Likewise, when the user equipment accesses the EPS through the E-UTRAN using the PMIPv6 between the S-GW and the P-GW, or when the user equipment accesses the EPS through the trusted non-3GPP access network using the PMIPv6 between the trusted non-3GPP access network and the P-GW, or when the user equipment accesses the EPS through the trusted non-3GPP access network using the DSMIPv6 or MIPv4, the PCEF located in the P-GW cannot accurately detect the change of the RAT type in the IP-CAN type in certain cases. At this point, the PCRF can only subscribe the IP-CAN type change notification at the BBERF, which detects and reports the event to the PCRF, which, in turn, reports the event to the AF.
In addition, when the user equipment accesses the EPS in the access scene described above and the AF requests resources for specific services, the AF may also subscribe a notification on whether the resources requested for the services are assigned successfully from the PCRF. After the PCRF receives the AF's subscription, it subscribes the event trigger at the BBERF. Upon the successful or unsuccessful assignment, the BBERF reports a successful or unsuccessful event to the PCRF, which, in turn, reports the event to the AF.
However, in a roaming scene where the UE is in home routing, that is, the P-GW is located in a home network and the S-GW or the trusted non-3GPP access network gateway is located in a visited network, if the PCC is deployed in the home network and the PCC is not deployed in the visited network, because the visited network cannot report the subscribed event to the PCRF, the PCRF cannot report the event to the AF either.
Likewise, when the UE accesses the EPS through the non-3GPP access network and the non-3GPP access network and the 3GPP network belong to different operators, if the PCC is deployed in the 3GPP network and the PCC is not deployed in the non-3GPP network, because the non-3GPP network cannot report the subscribed event to the PCRF, the PCRF cannot report the event to the AF either.
In the prior art, the AF determines whether the PCC is deployed in the visited network in which the UE is located based on its own configuration information (e.g., roaming protocol), that is, it determines whether the current scene is the limited PCC deployment scene. When the visited network does not support the PCC, the AF will not subscribe certain events (e.g., the AF signaling transmission path state notification, the IP-CAN type change notification and the resource assignment request successful or unsuccessful notification) at the PCRF. The main problem with this method is that the configuration information is relatively complicated, especially when the AF is a third party offering services; the configuration information is difficult to be updated; and when the visited network, or some S-GWs in the non-3GPP network, or the trusted non-3GPP access gateway support the BBERF, the AF cannot simply decide whether to subscribe the events according to the visited network in which the UE is located.
Content of the Invention
A technical problem to be solved by the present invention is to overcome shortcomings of the prior art and provide a method and system for implementing limited policy and charging control such that an AF can know more conveniently whether the current deployment is the limited policy and charging control deployment (that is, PCC is not deployed in the visited network and the dynamic PCC is not supported).
In order to solve the problems described above, the present invention provides a method for implementing limited policy and charging control comprising:
a policy and charging rules function (PCRF) determining whether a visited network where a user equipment (UE) roams supports policy and charging control (PCC), and notifying an application function (AF) that the subscribed event cannot be reported if the visited network does not support the PCC.
The PCRF may send a message containing an identifier indicating the limited policy and charging control deployment to the AF.
In addition, after receiving the message containing the identifier from the PCRF, the AF performs no subscription of the event and/or cancels the subscription of the event based on the identifier.
In addition, the PCRF determines whether the visited network supports the PCC by the following manner:
the PCRF determines whether the visited network supports the PCC after receiving an IP-connectivity access network (IP-CAN) session establishment indication message or an IP-CAN session modification indication message; when a mobility protocol type (MPT) identifier contained in the IP-CAN session establishment indication message or IP-CAN session modification indication message indicates that the access does not use a general packet radio service (GPRS) tunneling protocol and the PCRF does not receive a gateway control session establishment indication message, it is determined that the visited network does not support the PCC.
In addition, the PCRF determines whether the visited network supports the PCC by the following manner:
the PCRF determines whether the visited network supports the PCC based on local configuration information as well as an IP address of an access gateway in the visited network and/or a care of address of the UE and/or an IP address of a service gateway.
In addition, the PCRF determines whether the visited network supports the PCC by the following manner:
a policy and control enforcement function (PCEF) determines whether the visited network supports the PCC based on local configuration information as well as an IP address of an access gateway in the visited network and/or a care of address of the UE and/or an IP address of a service gateway and notifies the PCRF of a determination result, and the PCEF determines whether the visited network supports the PCC based on the determination result.
In addition, after receiving an application/service information message or event subscription message sent by the AF, the PCRF puts the identifier indicating the limited policy and charging control deployment into a corresponding response message to send to the AF.
In addition, when the UE switches to an access gateway not supporting a bearer binding and event reporting function (BBERF), the PCRF notifies the AF that the subscribed event cannot be reported.
In addition, when the PCRF detects that the UE moves to a trusted non-3GPP access network supporting the PCC, a visited 3GPP access network or a home network, the PCRF sends a limited policy and charging control deployment recovery indication identifier to the AF.
The present invention also provides a policy and charging rules function (PCRF) which supports implementation of limited policy and charging control and is configured to determine whether a visited network where a user equipment (UE) roams supports policy and charging control (PCC) and notify an application function (AF) that the subscribed event cannot be reported if the visited network does not support the PCC.
In addition, the PCRF is configured to send a message containing an identifier indicating the limited policy and charging control deployment to the AF such that the AF performs no subscription of the event and/or cancels the subscription of the event based on the identifier.
In addition, the PCRF is configured to determine whether the visited network supports the PCC by the following manner:
the PCRF determines whether the visited network supports the PCC after receiving an IP-connectivity access network (IP-CAN) session establishment indication message or an IP-CAN session modification indication message; when a mobility protocol type (MPT) identifier contained in the IP-CAN session establishment indication message or IP-CAN session modification indication message indicates that the access does not use a general packet radio service (GPRS) tunneling protocol and the PCRF does not receive a gateway control session establishment indication message, it is determined that the visited network does not support the PCC.
In addition, the PCRF is configured to determine whether the visited network supports the PCC by the following manner:
the PCRF determines whether the visited network supports the PCC based on local configuration information as well as an IP address of an access gateway in the visited network and/or a care of address of the UE and/or an IP address of a service gateway.
In addition, the PCRF is configured to determine whether the visited network supports the PCC by the following manner:
a policy and control enforcement function (PCEF) determines whether the visited network supports the PCC based on local configuration information as well as an IP address of an access gateway in the visited network and/or a care of address of the UE and/or an IP address of a service gateway and notifies the PCRF of a determination result, and the PCEF determines whether the visited network supports the PCC based on the determination result.
In addition, the PCRF is configured to, after receiving an application/service information message or event subscription message sent by the AF, put the identifier indicating the limited policy and charging control deployment into a corresponding response message to send to the AF.
In addition, the PCRF is further configured to notify the AF that the subscribed event cannot be reported when the UE switches to an access gateway not supporting a bearer binding and event reporting function (BBERF).
In addition, the PCRF is further configured to send a limited policy and charging control deployment recovery indication identifier to the AF when detecting that the UE moves to a trusted non-3GPP access network supporting the PCC, a visited 3GPP access network or a home network.
The present invention also provides a system for implementing limited policy and charging control comprising the policy and charging rules function (PCRF) and application function (AF) described above.
A system for implementing limited policy and charging control in accordance with the present invention may comprise a UE, a PCRF, an AF and a visited network where the UE roams.
The PCRF is configured to determine whether the visited network supports the PCC, and send a message containing an identifier indicating the limited policy and charging control deployment to the AF if the visited network supports the PCC.
In addition, after receiving the message containing the identifier, the AF performs no subscription of the event and/or cancels the subscription of the event based on the identifier.
To sum up, using the method and system in accordance with the present invention, the AF can be notified more conveniently and accurately of the current policy and charging control deployment situation when the limited policy and charging control is implemented (i.e., when the visited network does not support the PCC). Moreover, the AF may perform the corresponding operations, such as inexecution of the subscription of the event or cancellation of the subscription of the event, according to the current policy and charging control deployment situation, thereby saving system resources.